Sound system



g- 11, 1964 M. J. LONDON ETAL 3,144,092

scum: SYSTEM Filed April 4, 1962 TO AMPLIFIER 'IIIIIIIII INVENTORS. Vic/me? cl Laredozz BY M'Ffz'am Deasey M, W W zAos /A-o a M A TO SPEAKERS i 2 ATTORNEY 3,144,092 Patented Aug. 11,, 1964 3,144,092 SOUND SYSTEM Michael J. London and William Deasey, both of Old Glen Road, Morristown, NJ.

Filed Apr. 4, 1962, Ser. No. 185,096

3 Claims. (Cl. 181-27) 1 The invention relates generally to sound systems, and specifically to sound systems in which the transducers revolve, each directing its output successively over the area around the center of revolution.

It is among the objects of the invention to provide a revolving sound reproduction system.

It is another object of the invention to blend non-uniform directionally radiated sound frequencies from a transducer so as to eliminate any directional effect of a transducer with respect to the radiation of certain frequencies or portions of the audible sound spectrum. Yet another object of-the invention is to produce a 'sound system with a flat frequency response.

A still further object of the invention is to produce a reinforced. and improved sound from a transducer.

A still further object of the invention is to produce with maximum efficiency, a non-direction sound system.

Another object of the invention is to eliminate transducer placement problems in order to attain uniform sound dispersion over a chosen area.

These objects and advantages as well as other objects 'and advantages may be attained by the device shown by way, of illustration in the drawings in which:

FIGURE 1 is an elevational view of the sound system with-the foreground speaker removed in order to showthe construction;

. FIGURE 2 is a perspective view of the assemblage; FIGURE 3 is a perspective view of mercury cups and leads for supplying power to the transducers while rotating;

United States Patent Office where some part of the sound spectrum is defective, i.e.

although the transducer may be devised to give a relatively flat response over the entire range of audible frequencies, some areas of the space around the transducer or .transducers will be found to be non-uniform in the .quality of the response heardcertain portions of they? vsound spectrum will be exaggerated. The problem is especially compounded where a number of transducers are required to cover an 'area in which an audience is disposed over 360 about a center. The fans of sound emanating from the transducers are overlapping in some areas, producing reinforcement of some frequencies and nullification of others. Even when high quality components are relied upon, the audible sound may be lifeless and artificial.

It has been found that if a number of transducers are arranged with their fan of radiation in a generally horizontal position with respect to vertical axis upon which they are mounted, and the central axis is rotated, the audible effect with gathering speed will be a slow wowing, the wow gradually building in beat frequency with the increasing speed of rotation, until the wowing or pulsing disappears. At this speed, any position around the transducers at any point of the 360 rotation defined by their rotation, will have sound quality which is indistinguishable from the sound quality at any other point. The only difference is the loss of intensity as the listener moves away from the center. But even more unexpected than the disappearance of the wow,

and the uniform sound intensity, is improvement in the .quality of the sound. Higher frequencies which. before might only be detected in certain areas about the transducer are now heard uniformly throughout the entire area. Likewise, lower frequencies which might previous- .ly have been heard only in certain areas, are now heard together with the higher frequencies in the entire area.

Both high and low frequencies improve in quality and intensity, and the overall effect is enhanced brilliance and naturalness of sound. This result is especially dramatic in the case of low quality transducers which ordinarily are highly directional for certain frequencies.

When they reach the speed of rotation where the wow disappears, uniformity of radiated sound is greatly improved over what is heard when the transducer is standing still. It may be theorized that the animation effect that the eye sees when intermittently viewing rapidly moving pictures also applies to other modalities, in this instance to the ear. Frequencies only perceived at certain areas now sweep every location; although frequency response might not have been flat at every location, all 25 ducer, and blend together in one balanced, flat sound.

frequencies now sweep every location around the trans- Referring now to the drawings in detail, four transducers 11 are mounted with the central axis'of their voice coils disposed horizontally facing from each other. The transducers 11 shown all have the conventional magnet and voice coil housing 12, and basket support 13 for the cone. The ends of the housings 12 are attached to a central member of block 14. The block 14 acts as asupport, and is held up by a column 15 a suitable distance on a circular table 16. The edges pattern of the transducers 11 is transformed into a uniform distributional field. The field is flat and free of directionality. The coverage that is obtained is more uniform than would be obtained from many transducers of a stationary system. Much less power is required by the few transducers utilized in the present system.

Furthermore, less power is found to be needed to get the more uniform area distribution of sound with only the lesser number of transducers now utilized.

In order to convey the electrical impulses to the transducers while revolving, many means are available. Brushes contacting slip rings (not shown) will induce a mechanical noise into the system. An induction coil for picking up the impulses (not shown) may be utilized. The transmission of the driving force for activating the transducers 11 is efliciently accomplished by having a first mercury cup 21 on the top of the block 14, coincident with the axis of rotation of the block 14. Surrounding this first mercury cup 21 is a second or annular mercury cup 22. They are each connected to the leads 23, 24 from the transducers. Lead lines 23 and 24 are designated 1 and 2 in FIGURE 3. Adjacent to the rotating table 16 is a column 23' carrying the lines for carrying the signal to the transducers 11. This column 23' extends horizontally over the block, and down toward the mercury cups 21, 22. The leads 25, 26 extend out of the end of the column and into the mercury 27 in the cups 21, 22. The cups 21, 22 are arranged concentrically with the axis of rotation so that the leads will ducers.

at all times during rotation maintain contact with the mercury 27 in the cups 21, 22 without touching the metallic conductive cup itself. Mercury 27 is deposited in the cups to a level sufficient to reach over the end of the leads 25, 26. A film of high flash-point oil 28 may be floated on the mercury .27 to minimize arcing'and keep impurities, dust and dirt from contaminating the mercury.

A four transducer system operates satisfactorily at approximately forty-five to eighty revolutions per minute. Small transducers operate with complete freedom from wow at the higher rate of speed within that range, while larger transducers are found to operate free of wowing without attaining the higher speed of the range indicated. Perhaps a most surprising aspect of the -With the transducers stationary, feedback may be experienced at certain volume levels, depending upon the placement and directionality of the microphone .and trans- However, when the transducers are made to revolve, the feedback effect disappears and the volume may be greatly increased without reaching the microphone feedback point.

Although the invention illustrated by the drawings indicates the use of four transducers, a greater or lesser number may be used, with an increase in speed of rotacrease in -the speed of rotation if a greater number of .transd-ucers is used. With transducers that are directional, whose cone of radiation approximately subtends an arc of 90, four transducers will ordinarily be suf- .ficient, but the invention is to be understood as not limited to that number. y

Although we have shown, by way of illustration of the invention, transducers radiating in a generally horizontal plane, it is to'be understood that the focus of radiation may be changed. Whatever the area or direction may be that is scanned by thetransducers, a blended .have substitutes which may perform a substantially similar function; such substitutes may be known as proper.

substitutes for the said components and may have actually been known or invented before the present invention; these substitutes are contemplated as being Within the scope of the appended claims, although they are not specifically catalogued herein.

What is claimed:

1. A sound system comprising:

(a) a rotatable mounting for a transducer, (b) a transducer attached to the mounting,

(c) means connected to the mounting for a transducer.

.tion if a lesser number is used, and a permissible deto rotate continuously the mounting at a speed sufficient to make pulsing imperceptible,

(d) means connected to the transducer to conduct electrical impulses corresponding to sound to the transducer as it revolves, said means comprising (e) a cup attached to the mounting and electrically connected to the transducer,

(1) an electrically conductive fluid in the cup,

(g) a stationary electrically conductive lead in contact with the fluid in the cup.

2. A sound system comprising (a) a rotatable mounting for a transducer,

(b) a rans ucer atta he t th mounting,

(0) means connected to the mounting for a transducer to rotate continuously the mounting at a speed sufficient to make pulsing imperceptible,

(d) means connected -to the transducer to conduct electrical impulses corresponding to sound to the transducer as it revolves, said vmeans comprising (e) a first cup disposed concentrically with the axis of rotation of the mounting and electrically connected to the transducer,

(f) a second annular cup disposed concentrically with the axis of the mounting, and electrically connected to the transducer,

(g) an electrically conductive fluid in the cups,

(h) stationary electrically conductive leads in contact with the fluid in the cups.

3.' A sound system comprising (a) a rotatable mounting for an unbafiled plurality of transducers,

(b) four transducers attached to the mounting and positioned to emit sound in a general horizontal outward direction, and disposed at 90 around a circle from each other, i

(c) a motor operably connected to the mounting to drive it continuously at a rate of approximately 45 to revolutions per minute and to make pulsing imperceptible,

('d) a first cup disposed concentrically with the axis of rotation of the mounting and electrically connected to the transducers,

(e) a second annular cup disposed concentrically with the axis of rotation of'the mounting and electrically connected to the transducers, I

(1) an electrically conductive fluid in the cups,

(g) stationary electrically conductive leads, each in contact with the fluid in one cup as they revolve, (h) a column for holding the leads in contact with the fluid in the cups.

References Cited in the file of this patent I UNITED STATES PATENTS 2,114,680 Goldsmith Apr. 19, 1938 2,491,674 Markowitz Dec. 20, 1949 2,813,928 Mizrahi et a1. Nov. 19, 195.7 2,995,054 'Le'slie Aug. 8, 196.1 3,069,958 Arsem et al. Dec. 24, 1962 

1. A SOUND SYSTEM COMPRISING: (A) A ROTATABLE MOUNTING FOR A TRANSDUCER, (B) A TRANSDUCER ATTACHED TO THE MOUNTING, (C) MEANS CONNECTED TO THE MOUNTING FOR A TRANSDUCER TO ROTATE CONTINUOUSLY THE MOUNTING AT A SPEED SUFFICIENT TO MAKE PULSING IMPERCEPTIBLE, (D) MEANS CONNECTED TO THE TRANSDUCER TO CONDUCT ELECTRICAL IMPULSES CORRESPONDING TO SOUND TO THE TRANSDUCER AS IT REVOLVES, SAID MEANS COMPRISING 